CHAPTER XI. 



SOME PHYSIOLOGICAL RELATIONS OF VEGETABLE PROTEINS TO THE 

 ANIMAL ORGANISM AND THE BIOLOGICAL RELATIONS OF SEED 

 PROTEINS TO ONE ANOTHER. 



A. Toxalbumins. 



THE existence of toxic substances in the seeds of Ricinus and Abrus 

 was long ago recognised, but the first attempt to isolate the toxin was 

 made in 1884 by Warden and Waddell (566), who obtained from the 

 seeds of Abrus precatorius a substance which they considered to be a 

 protein, and to which they gave the name abrin. 



In 1887 Dixson (92) obtained, by neutralising a hydrochloric acid 

 extract of the seeds of Ricinus communis with sodium carbonate, a 

 precipitate which contained the toxic substance of this seed, and he 

 made extensive experiments with a view to purifying the product thus 

 prepared. His final preparation, which was very toxic, contained 

 much protein. 



In 1887 Sidney Martin (263) found that the protein substance 

 forming the abrin of Warden and Waddell consisted of two proteins, 

 one of which was a globulin coagulating at 75 to 80 and precipitated 

 by saturating its solutions with sodium chloride or magnesium sul- 

 phate, and the other an albumose. 



Stillmark (525) in 1888 ascribed the toxic action of Ricinus seeds 

 to a protein which he obtained by precipitating a sodium chloride 

 extract of the seed with magnesium sulphate or sodium sulphate, dis- 

 solving the precipitate in water and dialysing away the salts. Stillmark 

 named this substance ricin and considered it to be either a globulin or 

 a ferment. He also found that, in addition to its toxic properties, it 

 caused agglutination of a suspension of red blood corpuscles. 



Martin and Wolfenden (266) in 1889 described the physiological 

 activity of the globulin of Adrus, and at the same time Martin (265, 

 264) studied the toxic action of the albumose which he separated 

 from the globulin by coagulating the latter by long digestion with 

 alcohol. 



Ehrlich (102) made the important discovery, in 1891, that animals 



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